Feasibility study : eradication of kudzu with herbicides and revegetation with native tree species in two National Parks

The purpose of this two-phase study was to determine whether it is feasible to reclaim land infested with kudzu. The first phase dealt with finding a safe and effective method of eradicating kudzu from a given area, while the second phase dealt with revegetation of the same area. Experimental plots were located at Chickamauga and Chattanooga National Military Park on Lookout Mountain and at Cumberland Gap National Historical Park.

The first phase consisted of testing the effectiveness of four different herbicide treatments. The treatments were 1) June application of Roundup (glyphosate), 2) August application of Roundup, 3) Velpar (hexazinone), and 4) Velpar followed by Roundup. Results of the herbicide study indicated that Velpar alone was not effective in controlling kudzu. Velpar was only 7% effective at Lookout Mountain and 20% effective at Cumberland Gap. Roundup treatments ranged in effectiveness from 41% to 93%, with the August treatment having a very high 91-93%.

The second part of the study consisted of 12 different revegetation treatments superimposed on the same plots which had previously been treated with herbicides. Seedlings of three different native tree species were planted with and without mulch and with and without a seeded ground cover.

All three tree species, shortleaf pine, yellow-poplar, and black walnut had good early survival. Results were mixed with respect to the effect of mulch and annual ryegrass on seedling survival and kudzu cover. Ryegrass had a slight negative effect on seedling survival, while mulch had only a small positive effect. Mulch had a slight negative impact on kudzu cover, but only at Cumberland Gap. Ryegrass exhibited a rather pronounced negative effect on natural herb cover.

The use of Roundup to control kudzu is promising based on the results of this study. Late season applications appear to be more effective than early season applications. Revegetation can be accomplished successfully either by natural regeneration or by active revegetation methods.